Patients with end stage kidney failures who do not receive a kidney transplant must undergo either hemodialysis (HD) or peritoneal dialysis (PD). In hemodialysis waste products and extra fluid is removed by a special kind of filter. A vascular access is needed to withdraw the blood and to return it in a purified state to the patient. In peritoneal dialysis a dialysis solution is infused into the abdomen by means of a catheter. In the dialysis solution wastes and extra fluid from blood are accumulating and then withdraw by draining the dialysis solution.
For both dialysis modalities the requirement of a chronic intra-corporeal access poses a challenge and is associated with a high level of morbidity.
In peritoneal dialysis a standard catheter is used. The catheter has polyester cuffs which merge with scar tissue to keep it in place. Since the catheter is sticking out from the skin between dialysis sessions it is frequently displaced, which increases the risk of wound irritation and infection.
Three access methods are available in hemodialysis: a) arteriovenous fistula (AV fistula); b) arteriovenous graft (AV graft); and c) venous catheter (VC). In the preferred method the provision of an AV fistula requires long-term planning, since a usable fistula only develops over time; in rare cases the development may take as long as two years. On the other hand, a properly formed fistula is less likely than other kinds of AV access to form blood clots or become infected. About 70% of all dialysis patients end up with an AV fistula. If the patient has small veins that won't properly develop into a fistula, a vascular access that connects an artery to a vein using a synthetic tube or graft can be inserted under the skin. Compared with properly formed fistulas grafts tend to have more clotting and infection problems. The need to be replaced sooner and more sparsely used than fistulae.
If kidney disease is progressing quickly there may not be time enough to get a permanent vascular access before dialysis must be started. It may then be necessary to use a venous catheter as a temporary access. The catheter is inserted in to a vein in the neck, chest, or leg near the groin. The catheter has two chambers or conduits to allow blood from in two directions, to and from the vein. Once a catheter has been placed insertion of a needle is no longer required. However, catheters are not ideal for permanent access. The can clog, become infects, and cause narrowing and irritation of the veins in which they are placed.
Despite the aforementioned problems with permanent catheters about 20%-30% of all hemodialysis patients end up with them as chronic access. FDA's Annual Registry Report for 2009 states that “Despite ongoing initiatives to reduce catheter use . . . the use of catheters has remained at 17-18 percent since 2003”.
Similarly to the PD catheter the frequent movement of the access tube induces an increased risk of infection and wound irritation. Another risk for bacterial or mold infection is constituted by the use of access ports comprising membranes for injection/withdrawal of fluid. Therefore membranes intended for penetration by a hypodermic needle or similar should be avoided in permanently attached/tissue integrated venous access ports.
In view of the foregoing the provision of an improved device for permanent vascular access for hemodialysis is highly desirable.
Also desirable is the provision of an improved device for single lumen permanent vascular access, such as for repeated infusion into the blood stream, in particular infusion of solutions or suspensions of nutrients, pharmaceuticals, vitamins, and salts.
Devices for permanent venous access, such as the ones disclosed in WO 92/21403 A, WO 92/13590 A, WO 99/20338 A, WO 2009/002839 A1, U.S. Pat. No. 7,708,722 B2, U.S. Pat. No. 7,846,139 B2, U.S. Pat. No. 7,772,314 B2, U.S. Pat. No. 8,079,987 B2, and U.S. Pat. No. 8,282,610 B2, are known in the art.
Furthermore it is desirable to provide an improved device for peritoneal access, such as for peritoneal dialysis or for administration of drugs to a patient via the peritoneum, for instance administration of insulin to Type I diabetics who do no well respond to subcutaneous insulin.